Inflatable dock seals are the subject matter of the O'Neal U.S. Pat. Nos. 3,303,615; 3,391,502; 3,391,503; and 3,714,745 and of the Sciolino U.S. Pat. No. 3,500,599. The structures shown in all of these patents are of complicated make-up, required special installation techniques and are expensive to maintain. The structure disclosed herein is designed to simplify and make less expensive manufacture and installation and to provide a structure which can be completed at its place of manufacture, ready for installation, and folded into a compact package, to facilitate shipping.